Method and apparatus for flame jet cutting

ABSTRACT

A cutter proper is provided with a burner having at its tip a nozzle that injects a combustion flame of oxygen and kerosene at supersonic speed. Thermit material is supplied to the flame jet that is injected by burning the oxygen and kerosene at supersonic speed whereby the concrete or stone material and the like is burnt at such high temperatures where said material to be cut is melted. The cutting body can be cut by melting without relying on destruction of human work by injecting the flame jet toward the cutting body.

United States Patent Hokao et a1.

METHOD AND APPARATUS FOR FLAME JET CUTTING Inventors: Zenjiro I-Iokao,Shimoyasumatu 50-80, Tokorozawa-chi, Saitama-ken', Taiitsu Makajima,Nakato 2482, Musashimurayama-chi, Tokyo, both of Japan Filed: May 8,1972 Appl. No.: 251,183

Foreign Application Priority Data May 12, 1971 Japan 46/32111 Oct. 6,1971 Japan t 46/79018 Jan. 28, 1972 Japan 47/10688 U.S. Cl. 299/14,110/22 B, 175/13,

431/4, 431/114, 143/158 Int. Cl. E21c 21/00 Field of Search 299/14;175/13, 14;,431/4,

[451 Feb. 12, 1974 [56] References Cited UNITED STATES PATENTS 3,116,798l/1964 Job 175/14 2,794,620 6/1957 Arnold et a1 175/14 2,392,353 1/1946Aitchison 175/13 2,470,999 5/1949 Meinckem, 110/22 B X 3,620,013 11/1971Rogers et a1 431/114X Primary Examiner-Ernest R. Purser Att0rney, Agent,or Firm-Meyer, Tilberry & Body [57] ABSTRACT A cutter proper is providedwith a burner having at its tip a nozzle that injects a combustion flameof oxygen and kerosene at supersonic speed. Thermit material is suppliedto the flame jet that is injected by burning the oxygen and kerosene atsupersonic speed whereby the concrete or stone material and the like isburnt at such high temperatures where said material to be cut is melted.The cutting body can be cut by melting without relying on destruction ofhuman work by injecting the flame jet toward the cutting body.

7 Claims, 6 Drawing Figures PATENTEDFEBIZIQH 3 ,791,697

SHEET 2 [IF 2 FIG. 3

METHOD AND APPARATUS FOR FLAME JET CUTTING This application pertains tothe art of cutting and more particularly to the cutting of stone-likematerials.

The invention is particularly applicable to cutting concrete, stonematerial and other materials similar to the concrete by a flame jet andwill be described with particular reference thereto; however, theinvention has broader application as will be more fully appreciated bythose skilled in the art.

Heretofore, concrete "and stone materials have been cut generally bymeans of chipping work by hand using hammer or chisel. This workcomprised cutting the concrete with the chisel by gradually destroyingit and the time and labor required for accomplishing the work wastremendous with the resultant work efficiency being quite low. Also, asthe chipping work was being carried out, numerous cracks were caused inthe stone by the action of striking the chisel. Because of thiscracking, the remaining portion of the cut concrete which was to be usedfollowing cutting frequently could not be used due to severe cracks.

In cutting relatively thin concrete plates, mechanical machines such asmotor saw and the like have heretofore been utilized. However, wear andtear of the component machine parts is excessively great and in the casewhere the machines must be used for extended time periods, valuable worktime is required for replacement and maintenance of the machinecomponents. Further, when cutting thick concrete blocks and the like,large cutting machines have been required which, in turn, increased thecosts and operational difficulties thereof.

The present invention contemplates a new and improved method andapparatus which overcame all of the above referred problems and othersand provides method and apparatus for flame jet cutting which is simple,economical and readily adaptable to use with different stone orconcrete-like materials having various thicknesses.

In accordance with the present invention, there is provided a method offlame jet cutting particularly adapted for use in cutting stone orconcrete-like materials. The method comprises the steps of providing acombustion flame jet comprised of oxygen and kerosene in a burner;ejecting the jet from the burner at a supersonic velocity; and,supplying a thermit to the jet following ejection from the burnerwhereby the material is cut by the simultaneous combustion of theoxygen, kerosene and thermit.

In accordance with a more limited aspect of the present invention, themethod further includes the step of cooling the burner by injecting acooling fluid onto the periphery of the flame jet.

In accordance with another aspect of the present invention, there isprovided an apparatus particularly adapted for use in flame jet cuttingof stone or concrete-like material. The apparatus includes a cutter headhaving a burner therein for permitting desired combustion of oxygen andkerosene therein to form a cutting flame jet; means for supplyingselected amounts of the oxygen and kerosene to the burner; means forpermitting escape of the jet from the burner at high velocity; and,means for continuously directing a cooling fluid at least around theouter periphery of the burner.

In accordance with another aspect of the present invention, theapparatus further includes means for directing a thermit material to theflame jet adjacent the burner and means for continuously supplying thethermit material to the directing means.

In accordance with still another aspect of the present invention, meansare provided to permit a continuous cooling fluid flow onto theperiphery of the flame jet at least from a position immediately adjacentthe burner during escape of jet from the burner.

In accordance with yet another aspect of the present invention, theapparatus includes means for muffling the noise created by apparatusoperation.

The principal object of the present invention is the provision of amethod and apparatus for flame jet cutting stone or concrete-likematerial.

Another object of the present invention is the provision of a method andapparatus for flame jet cutting which is simple.

Another object of the present invention is the provision of a method andapparatus for flame cutting which is efficient in use.

Another object of the present invention is the provision of a method andapparatus for flame jet cutting which is readily adapted for use withstone or concretelike materials of different types and sizes.

Still another object of the present invention is the provision of amethod and apparatus for flame jet cut ting which is inexpensive toemploy.

Still another object of the present invention is the provision of amethod and apparatus for flame jet cutting which provides improved cutsin stone or concretelike materials.

The invention may take form in certain parts and arrangements of parts,a preferred embodiment of which will be described in detail in thespecification and illustrated in the accompanying drawings which form apart hereof and wherein:

FIG. 1 is a flow sheet schematically showing a cutting device and a fuelsupply circuit according to the present invention;

FIG. 2 is a vertical cross-sectional view of a tip portion of theburner;

FIG. 3 is a flow sheet schematically showing a cutting device and a fuelsupply circuit according to the present invention in which the burnerincludes means for ejecting water from the burner tip so as to surroundthe jet flame;

FIG. 4 is a vertical cross-sectional view of the tip portion of theburner shown in FIG. 3;

FIG. 5 is an elevational view of the tip portion of the burner shown inFIG. 4; and,

FIG. 6 is a vertical cross-sectional view of a muffler mounted at a tipportion of the cutter head.

Referring now to the drawings wherein the showings are for purposes ofillustrating the preferred embodiment of the invention only and not forpurposes of limiting same, there is shown in FIG. 1 a burner 2 providedat a tip of a cutter head 1. An oxygen cylinder 35 supplies oxygen undera pressure of generally between 40-45 psi to burner 2 and a kerosenecylinder 4 supplies kerosene under a pressure of generally between 40-45psi to burner 2. A cylinder 5 of high pressure nitrogen is employed tocause the kerosene to flow from cylinder 4 to burner 2. With referenceto FIG. 2, it will be seen that the tip portion of burner 2 is providedwith a rubber nozzle 6 and a combustion chamher 7 which is communicatedwith the nozzle. At the end of combustion chamber 7 spaced remote fromnozzle 6, there is provided an injector 9 threaded to a holder 8. Aplurality of injecting outlets l bored on the central portion ofinjector 9 are communicated with a central opening 11 in holder 8 andopening 11 is communicated with a kerosene supply pipe 12 for injectingkerosene as will hereinafter become apparent. The plurality of injectingoutlets 13 bored on external peripheral portion of injector 9 arecommunicated with an external peripheral opening 14 of the holder 8 withopening 14 being communicated with an oxygen supply pipe 15 whichsurrounds the external periphery of kerosene supply pipe 12. Theinjected kerosene is mixed with the oxygen through its atomization andis burned at high temperatures in the range of 3,500 to 8,800K incombustion chamber 7 by its ignition at the tip of the burner 2. As themixture is ejected from nozzle 6, it is transformed to supersonic flamejet of Mach number -6. Simultaneously therewith, the external wallsurface of combustion chamber 7 is heated to a high temperature so thatit is necessary to effect continuous cooling thereof. In the preferredembodiment and for needed cooling, a sleeve 17 is provided between theexternal peripheries of nozzle 6, combustion chamber 7 and an outer tube16. A through-hole 18 is provided in sleeve 17 adjacent its base end andthe other end is disposed in a tight fitting contact with the externalperiphery of holder 8. Also, the opposite end of holder 8 is connectedto an inner tube 19 which surrounds the external periphery of oxygensupply pipe 15. Cooling fluid, which comprises water in the preferredembodiment, is supplied under a pressure of approximately liters perminute at a pressure of 4 to 6 psi to the space or channel formedbetween oxygen supply pipe and inner tube 19. From there, it isintroduced to the space or channel formed between combustion chamber 7and sleeve 17 through an opening 20 in holder 8 to cool the externalwall of the combustion chamber. It is then discharged to the outside bypassing through hole 18 and thence through the space or channel formedbetween sleeve 17 and outer tube 16. In FIGS. 1 and 3 of the drawings,reference numeral 21 generally designates a tank for holding the coolingwater and numeral 22 generally designates a pump for pumping the waterto the cutter head.

A thermit powder supply pipe 23 is provided along the outside of cutterhead 1 and includes a tip formed with jetting port 24 generally directedtoward the tip direction of the burner 2. The thermit material or powderis conveniently stored in a thermit powder container 25 and is suppliedunder pressure to the end of burner 2 by pressurized air from acompressor 26 from where it is jetted outwardly of port 24 toward theflame jet. When the flame jet is directed against a body 27 which is tobe cut, that is, concrete material or the like, the thermit is burned onthe surface of the cut 28. The flame at that point becomes one of hightemperature so that body 27 is effectively melted at out 28. The moltenmaterial is caused by the melting or cutting action and is removed fromthe area of the cut by the pressure, generally in the range of from l0l5psi, of the flame jet itself. The material from the cut also acts tomelt additional successive new surface of body 27 so that the area ofthe cut is rapidly melted. In practice, the cutting speed is about 6-8meters per hour when reinforced concrete plate having a thickness of 10cm is being cut.

Although the preferred embodiment of the invention employs thermitpowder which is supplied by means of a pipe, it will be understood thatthe powder is not necessarily required and that a thermit rod may beintermittently inserted into the cutting surface of the concrete.

The concrete surface which has been cut in a manner as hereinabovedescribed eliminates the cracks which have heretofore occurred in thecase of the chiseling type of cutting work. Thus, the shape of theconcrete surface when using the subject invention may be favorablymaintained. Accordingly, regardless of the thickness and the size of theconcrete material, cutting can be effected so that machining such asboring and the like, is made possible. Again, it will be appreciatedthat the subject invention may be utilized not only for the concrete butalso for stones and other concrete-like materials.

Since, body 27 is heated to high temperatures at the periphery of thatportion to be cut during the time of cutting, it is desirable to providemeans for cooling that peripheral area. In the situation where the bodyto be cut is comprised of concrete, cooling is most advantageous asconcrete has properties of showing brittleness to the heat which, ofcourse, is not desired.

The device shown in FIGS. 3, 4 and 5 is designed to cut the body whileproviding cooling to an extent that the thermal influence can be ignoredeven if it is highly influenced by the heat.

In the device shown in FIG. 4, a flow passage 29 for the cooling fluidis formed on the external peripheries of combustion chamber 7 and oxygensupply pipe 15. The cooling fluid is fed under pressure from tank 21 bymeans of pump 22. The cooling fluid which has cooled the external wallof combustion chamber 7 is jetted outwardly from the tip of the cutterhead through a plurality of jetting out ports 30 formed on the peripheryof the opening portion of the tip of burner 2. By this arrangement,jetting cooling water surrounds the periphery of the flame jet tothereby impinge the cutting area to effect cooling and shields thesounds of the operation of the flame jet.

As described hereinabove, the cutting body is cooled by the coolingfluid at the periphery of the cutting area while it is being cut so thatthe cutting action does not cause thermal influence on a cutting bodywhich has a tendency of thermal alteration. Thus, the shape of the cutarea in the body may be maintained as desired. Since the cooling fluidis jetted outwardly from the tip of burner, a continuous circulationcircuit for the fluid is not required in order that the device itselfmay be constructed in a light weight and compact form. Furtheradvantages are that the use of a special heat resisting alloy is notrequired at the tip portion of burner 2 and that the noise caused byoperation of the flame jet is shielded so as to provide soundinsulation.

The apparatus shown in FIG. 6 shows means for muffling the sound of theflame jet. The jet cutter according of the present invention has anextremely great injection sound of the flame jet. Because of this, thenoise level could cause problems with persons near the apparatus duringits operation. This is particularly true when the apparatus is utilizedin a residential area.

Therefore, and with reference to FIG. 6, a muffler 31 is provided whichis comprised of an inner tube 32 and an outer tube 34 disposedconcentrically therearound so that there is a clearance or channel 33therebetween. Clearance 33 is sealed at both ends of inner tube 32 andouter tube 34. The inner tube is formed so as to include a plurality ofbulged portions 35 along its periphery which, in turn, include aplurality of water jetting out holes 36 on the sides thereof. Acylindrical mounting portion 37 is formed on the base end of muffler 31with a jet cutter 38 inserted thereinto and affixed thereto by means ofany convenient retaining members 39 such as screws and the like. Also, awater feeding port 40 is formed on the muffler with a hose 42 leadingfrom a pump 41 connected to port 40.

When jet cutter 38 is used, the ignition is carried out in the conditionwhere the tip of the jet cutter is caused to protrude to the outside ofmuffler 31. After ignition and when the flame is stabilized, the muffleris caused to move forward so that the tip of jet cutter 38 is situatedgenerally at the vicinity of mounting portion 37 and retained in thatposition by means of retaining members 39. In this condition, pump 41 isoperated so that pressurized fluid or water is introduced into theclearance or channel 33 from water feeding port 40 such that the insideof clearance 33 is filled with the fluid. The fluid is then caused tojet outwardly from ports 36 of tube 32 to form a film of water on theperiphery of the flame. The noise of operation of the jet flame isthereby shielded by the wall of water in clearance 33, the film of waterin the periphery of the jet flame and the irregular surface formed bythe bulged portions of the inner tube.

The invention has been described with reference to the preferredembodiment. Obviously, modification and alteration will occur to othersupon the reading and understanding of this specification. It is myintention to include all such modification and alterations insofar asthey come within the scope of the appended claims or the equivalentsthereof.

Having thus described our invention, we now claim:

1. A method of cutting a stone or concrete-like material comprising thesteps of: providing a combustion jet flame comprised of oxygen andkerosene in a burner; ejecting said jet flame from said burner atsupersonic velocity; supplying a thermit to said jet flame followingejection from said burner; ejecting a cooling fluid about the peripheryof said jet flame; directing said jet flame and thermit against an areaof the material to be cut, and directing said cooling fluid about theperiphery of the area of the material to be cut.

2. An apparatus for flame cutting stone or concretelike materialcomprising: a jet flame cutter head adapted to provide continuouscombustion of a mixture of oxygen and kerosene received therein to forma jet flame; means to supply metered amounts of oxygen and kerosene tosaid jet flame cutter head; means to ignite and sustain combustion ofsaid oxygen and kerosene to provide a jet flame in said jet flame cutterhead; means to eject said jet flame from said flame cutter head atsupersonic velocity; means to provide a coolant about the periphery ofsaid flame cutter head; means for supplying thermit to said jet flame;and means to direct said coolant about the periphery of said jet flame.

3. The apparatus defined in claim 2, including a thermit powder supplypipe with a nozzle positioned adjacent the tip of said flame cutterhead; a thermit powder container; and thermit powder pressure feedingmeans connected to said container to supply thermit powder underpressure to said powder supply pipe nozzle.

4. The apparatus of claim 2, wherein said jet flame cutter head includesa combustion chamber having a nozzle at one end; injector means forinjecting a mixture of oxygen and kerosene into said chamber, saidinjector means being disposed on the side of said chamber opposed tosaid nozzle; an oxygen supply pipe connected at one end to said injectormeans and at the opposite end to oxygen supply means; a kerosene supplypipe connected at one end to said injector means and at the opposite endto a kerosene supply means; a thermit powder supply pipe secured at oneend to the tip of said jet flame cutter head and at the other and to asupply of thermit powder; and a liquid cooling tube encircling said jetflame cutter head connected to a supply of liquid coolant.

5. The apparatus of claim 4, including a plurality of liquid coolantoutlet ports in the tip of said flame cutter head communicating withsaid liquid cooling tube and adapted to direct coolant about theperiphery of said jet flame and about the periphery of impingement ofsaid jet flame against said material to be cut.

6. The apparatus of claim 2, including a noise muffler comprising anelongated inner tube dimensioned to be slidably received co-axially oversaid jet flame cutter head, said inner tube including a plurality ofaxially spaced apart annular pockets projecting radially outwardly fromsaid tube; an outer tube co-axially received over said inner tube andsealed to provide a closed fluid chamber there between, port means insaid annular pockets to provide communication between said inner andouter tubes; and means to introduce a fluid coolant under pressure intosaid chamber to flow through said port means into said inner tube tomuffle the sound of, and impinge the periphery of, said jet flame.

7. The apparatus defined in claim 6, including means to adjustablyposition said muffler longitudinally along said jet flame cutter head.

1. A method of cutting a stone or concrete-like material comprising thesteps of: providing a combustion jet flame comprised of oxygen andkerosene in a burner; ejecting said jet flame from said burner atsupersonic velocity; supplying a thermit to said jet flame followingejection from said burner; ejecting a cooling fluid about the peripheryof said jet flame; directing said jet flame and thermit against an areaof the material to be cut, and directing said cooling fluid about theperiphery of the area of the material to be cut.
 2. An apparatus forflame cutting stone or concrete-like material comprising: a jet flamecutter head adapted to provide continuous combustion of a mixture ofoxygen and kerosene received therein to form a jet flame; means tosupply metered amounts of oxygen and kerosene to said jet flame cutterhead; means to ignite and sustain combustion of said oxygen and keroseneto provide a jet flame in said jet flame cutter head; means to ejectsaid jet flame from said flame cutter head at supersonic velocity; meansto provide a coolant about the periphery of said flame cutter head;means for supplying thermit to said jet flame; and means to direct saidcoolant about the periphery of said jet flame.
 3. The apparatus definedin claim 2, including a thermit powder supply pipe with a nozzlepositioned adjacent the tip of said flame cutter head; a thermit powdercontainer; and thermit powder pressure feeding means connected to saidcontainer to supply thermit powder under pressure to said powder supplypipe nozzle.
 4. The apparatus of claim 2, wherein said jet flame cutterhead includes a combustion chamber having a nozzle at one end; injectormeans for injecting a mixture of oxygen and kerosene into said chamber,said injector means being disposed on the side of said chamber opposedto said nozzle; an oxygen supply pipe connected at one end to saidinjector means and at the opposite end to oxygen supply means; akerosene supply pipe connected at one end to said injector means and atthe opposite end to a kerosene supply means; a thermit powder supplypipe secured at one end to the tip of said jet flame cutter head and atthe other and to a supply of thermit powder; and a liquid cooling tubeencircling said jet flame cutter head connected to a supply of liquidcoolant.
 5. The apparatus of claim 4, including a plurality of liquidcoolant outlet ports in the tip of said flame cutter head communicatingwith said liquid cooling tube and adapted to direct coolant about theperiphery of said jet flame and about the periphery of impingement ofsaid jet flame against said material to be cut.
 6. The apparatus ofclaim 2, including a noise muffler comprising an elongated inner tubedimensioned to be slidably received co-axially over said jet flamecutter head, said inner tube including a plurality of axially spacedapart annular pockets projecting radially outwardly from said tube; anouter tube co-axially received over said inner tube and sealed toprovide a closed fluid chamber there between, port means in said annularpockets to provide communicatIon between said inner and outer tubes; andmeans to introduce a fluid coolant under pressure into said chamber toflow through said port means into said inner tube to muffle the soundof, and impinge the periphery of, said jet flame.
 7. The apparatusdefined in claim 6, including means to adjustably position said mufflerlongitudinally along said jet flame cutter head.